1. Field of the Invention
The present invention relates to a forced air supply combustion apparatus that supplies primary air with a combustion fan.
2. Description of the Related Art
Conventionally, as a combustion apparatus of this type, there is known a combustion apparatus in which, in a combustion housing, a burner unit including a plurality of burners provided side by side in the horizontal direction is arranged and an air supply chamber in a lower part partitioned by a partition plate from an arrangement section of the burner unit and a primary air chamber in a front part that stands from a front end of the air supply chamber are provided, the air from a combustion fan, which is connected to an air supply port opened on a bottom surface of the air supply chamber, flows to the primary air chamber through the air supply chamber, and the primary air is supplied from the primary air chamber to the respective burners of the burner unit (see, for example, Japanese Patent Laid-Open No. 7-318048).
In order to prevent the combustion fan from interfering with the other members, it may be inevitable to open the air supply port in a position biased to one side in the horizontal direction on the bottom surface of the air supply chamber. The air from the combustion fan naturally flows in the air supply chamber. Therefore, when the air supply port is opened in the position biased to one side in the horizontal direction, a pressure distribution in the primary air chamber becomes nonuniform and a supply quantity of the primary air to a part of the burners becomes excessively larger or excessively small.